"singular goal" is correct and usable in written English.
You can use it when referring to an objective that someone is aiming to achieve. For example, "She has a singular goal in mind: to win the race."
Making jewelry for movies was my singular goal.
To bring class to hip-hop, that was the specific singular goal I had".
"That is, and always will be, our singular goal every season.
Their singular goal is winning back the Senate in 2016, while making progress in the House.
Think about it: You've spent four (or five) years focused on the singular goal of graduating.
Are all college athletes pursuing a degree by default with the singular goal of becoming a professional athlete?
Since he took the reins in 2008, the team president Donnie Walsh has pursued a singular goal: to clear salary-cap space.
Food is the great marker of the day at Hickory Knoll — the singular goal toward which most labor and creativity tend.
In its simplest form, marketing has a singular goal: to connect with the right people, at the right moment, with the right messages.
That is, as something to be enjoyed moment by moment, inning by inning, night by night, rather than entirely focussed on the singular goal of winning a championship.
Mr. Gehry said that his singular goal, to make an intimate and comfortable concert hall, is actually a tribute to Mrs. Disney.
